We’re living in the very best time to be human so far. It wasn’t long ago that the world was living under the constant threat of global nuclear annihilation, before that two world wars, before that constant illness, famines, and other wars, etc. Long before that, just struggling to get enough food and shelter to survive.
The same goes for current working conditions/life. Some things are worse than 20 years ago but some are better.
For one thing, micro-plastics weren't in the brains and bloodstream of past populations. That said, doubtful anyone hesitant to have kids is under the delusion everything was always better in the past. I certainly wasn't when the time came to make those decisions.
Who is saying this?!
Regardless, there are 8 billion humans from a population pool that may have at times dropped to as few as a few hundred. So risk of human extinction is far less than the (very real) risk of making lives of future generations much shittier.
Why compare ourselves to China and not to a place like Argentina or wherever they take mid-day naps during weekdays? Because you don't want to fall behind in the global economic race. As the world becomes increasingly interconnected, there are going to be fewer and fewer protections for the local industries. For example, back in the 20th century it was possible to ban imports of various foreign goods, because those same products could be manufactured anywhere. But we're increasingly getting to the point where there are only 2 or 3 options for most of the tech products (mobile phones, computer operating systems, anything AI-related). In 20-50 years from now, things are only going to get worse. As a first-world country, you might still have a chance to be a relevant exporter in the mid and late 21st century, which will hopefully pay for the cost of importing everything else you can't manufacture locally. But you won't get there with siestas.